GEQDSK Viewer

A VS Code extension for visualizing tokamak equilibrium data stored in .geqdsk (G-EQDSK / g-file) files.

Features

• Right-click Context Menu: Plot or save any file as GEQDSK via right-click menu (works with any file extension)
• Plot or Save: Choose to display in a matplotlib window (X11) or save as PNG file
• CLI Command: Use geqdsk-viewer <file> [mode] from the terminal
• Equilibrium Visualization: Displays magnetic flux surfaces, plasma boundary, and key equilibrium parameters
• X-point Coordinates: Shows upper and lower X-point locations in the information panel
• Auto-install Dependencies: Automatically prompts to install required Python packages if missing

Requirements

• Python 3 with the following packages (auto-installed if missing):
  • numpy
  • scipy
  • matplotlib

The extension will automatically prompt you to install missing packages on first use.

Usage

VS Code (GUI)

1. Right-click on any GEQDSK file (any extension) in the Explorer or Editor
2. Select one of the following from the context menu:
   • "GEQDSK Viewer: Plot(no save)" - Opens a matplotlib window via X11 (requires display)
   • "GEQDSK Viewer: Save" - Saves as <filename>.png in the same directory (works on remote/SSH)
3. View the equilibrium plot

Use the Command Palette (Cmd+Shift+P / Ctrl+Shift+P) and search for "GEQDSK Viewer".

Terminal (CLI)

Install the CLI alias via Command Palette → "GEQDSK Viewer: Install 'geqdsk-viewer' command", then:

# Plot (opens X11 window)
geqdsk-viewer g123456.01000

# Explicitly specify plot mode
geqdsk-viewer g123456.01000 plot

# Save as PNG instead of displaying
geqdsk-viewer g123456.01000 save

Tip: Use save mode when working over SSH/Remote, as matplotlib windows require a display.

What is GEQDSK (G-EQDSK)?

GEQDSK (G-EQDSK, also known as "g-file") is a standard file format widely used in fusion plasma physics for storing MHD (magnetohydrodynamic) equilibrium data from tokamak devices. It contains:

• Plasma boundary shape
• Magnetic flux function (ψ)
• Pressure profile
• Safety factor (q) profile
• Toroidal current profile
• And other equilibrium parameters

For detailed file format specification, refer to the G-EQDSK documentation.

Credits

• GEQDSK Plotting Routine (eqdsk.py): Developed by SangKyeun Kim, Ph.D. (Princeton Plasma Physics Laboratory, PPPL)
• VS Code Extension Integration: Jaebeom Cho, JayMyoung Lee (3DST Lab, Seoul National University)

Known Issues

• Requires Python to be available in the system PATH
• Large GEQDSK files may take longer to process

Release Notes

0.0.7

• Simplified to single-file operation
• Right-click menu renamed: "Plot(no save)" and "Save"
• CHEASE-related code removed for lighter packaging
• Performance optimization (vectorized numpy operations)
• Proper attribution for original eqdsk.py author

0.0.4

• Added right-click context menu "GEQDSK Viewer: Plot geqdsk"
• Support for any file extension (not just .geqdsk)
• X-point coordinates displayed in the plot
• Plot opens in matplotlib window instead of saving PNG file

0.0.3

• Updated documentation with G-EQDSK specification link
• Added credits for PLARE Lab (SNU) and 3DST Lab

0.0.2

• Improved error handling
• Added progress notification

0.0.1

• Initial release
• Basic GEQDSK file viewing support

License

MIT

Enjoy visualizing your fusion equilibrium data!